Blackhand Edition also features a bunch of new indoor environments to skulk around in, which is always a plus. Not only are there now more diverse floor plans for the dozens of businesses and rackets you'll need to raid, but the four Family Compounds - the heavily defended fortresses you'll need to bomb in order to wipe each rival mob off the map - have all been redesigned with unique layouts to keep you on your toes. They're also now filled with breakable stuff, ranging from throwable bottles to electrical transformers that can fry anyone you throw into them.
A lot of subtler gameplay elements have been redesigned as well. The RPG-style system for leveling up your custom goon now offers more tangible benefits, with the skill upgrades now divided into "Enforcer" and "Operator" subsets. Operator skills will boost your powers of persuasion and enable you to do underhanded stuff like planting car bombs, while the Enforcer path is more direct - stronger attacks, better aim, etc. Spend enough points on one path or the other, and you'll earn the right to do completely new things, like pistol-whipping people to make a point.